Apparatus for feeding filamentary particles



A. ROSENBLATT ETAL 2,862,529

APPARATUS FOR FEEDING FILAMENTARY PARTICLES Filed Jan. 51, 1956 5Sheets-Sheet 1 INVENTORS ALEM/VDEK AflSf/VEZATT DONALD H PFEFFERLE Dec.2, 1958 A. ROSENBLATT ET AL' 2,862,529

APPARATUS FOR FEEDING FILAMENTARY PARTICLES 3 Sheets-Sheet 2 Filed Jan.31, 1956' INVENTORS ALfXANDEl? R05 E/VBL47 7 [MN/4L0 H PFEFFERLE Dec. 2,1958 A. ROSENBLQTT ET AL APPARATUS FOR FEEDING FILAMENTARY PARTICLES 3Sheets-Sheet 5 Filed Jan. 51, 1956 INVENTORS ALEXA/V05? RflJE/VELATTDONALD H. PFZFFERLE @464 ATTORNEY United States Patent 2,862,529MPMtA-TUS FQR FEEDING FILAMEN-TARY "PARTIQLES .AlexanderrRosenblatt andDonald Pfefierle, Williams- ;port, ,P,a assignors tosylvania Electric;Products Inc., .SalemQMaea, a. corporation. (ifs-Massachusetts Thisinvention elates-,toithe-manufacture of fiashilamps andsmoreparticularly to theintroductionnofaicombustible 1 1 1 3 int mfl-ashmpzbul .ln the manufacture of hash :lamps, filamentary par- ;ticles of acombustible metal material, -;such as .shredded ,afoiltforz-example areintroduced into the; lamp bulb. .The

;sh.re,dde.d :foil may :be formed by feeding a .sheet of the.eomhustible ;metal1material :into a suitable .cutting .ma- -:.chine,:sueh as :the .maehiue shown .in 1U. S. Patent j2;69.9;83;1;for;example.T;The shredded foilzprodncedby zthe :cutting :machinezis then ffedQtothe lamp :bulb. .A

method for introducing shredded foil into lamp bulbs disclosedinethe nopcndingyapplication of Bennett et al, Serial No.1192;224nfi1e32l:Qcotb.er;26, 195.0?11OW .U.:S. Patent-2,272,103.

An. object 10f it-his invention zisrto; introducexfilamentary particlesl-into iflashtlamp .bulbs.

Ano her-cobieet of thisiinventionis to provideapparatus gfQI. Efeedingfilamentary :particles jinto flash damp :bulbs.

Affurther ;obj,ectiis:to-;p1:ovide, apparatus for :automatipally gfeeding filamentary particles to lamp 'iblilbs married:to:-;loading.-position by.a. conveyor.

These and otherobjects, advantages and featuresare ;attained,,inaccordancewith the;pri-nciples ofonriinvention, by reciprocating 'a:nozzle, preferably rotatable, into .andnut: of;-a:l.ampzbulb carried:by an indexing conveyor. The reciprocatingestroke :of the nozzle issynchr.onized -,with :the :indexing ;of the bulb-carrying conveyorl'sothat tthe forward stroke -.:of IhCTIlOZZIG ;oc.curs:after :a :bulb :hasbeen; carried :hy the;conv.eyor into register .with: the: nozzle,

and-the return stroke occurs aftera charge of filamentarypartiales,:.sueh as shredded foil, forexample, has :been delivereditothe bulb :through the nozzle. A pneumatic vsystem employed-toicarryacharge of shreddedifoil from .a supply thereof :to the nozzle is:actuated intermittently :and is synchronized withrt-he reciprocationofthe nozzle to provide ;for the :delivery of a charge .of shredded foil.to the;no z-zle when thetnozzlegis-in .deliveryposition with vrespectto' a bulb.

This invention is further characterized by the provision :ofa -pair .ofreciprocating nozzles, preferably ro- ;tatable,-to whichshreddedzfoilisfedfrom a:common sup- -ply,ifor alternately delivering a charge .-ofshredded foil :to1a bulb ontone conveyonand then to;another bul.b.onranothertconveyor. .Thus the outputtof alsingle foil'shreddingimachineisemployedto provide achargeof shredded foilttoibulbs-carried-on twoseparateconveyors.

:In the vspecificenibodiment of the sinvention 'shown in theaccompanying drawings,

Figure 1.:is a plan :view of apparatusfor introducing a quantity ofshredded foil into llamp bulbs, and includes also iaeportion .ofapparatus which may :be employed to v.shred foil and a portionof theconveyors :which carry bulbs into foilefilling position.

Figure 2 isa sideelevational view, partly in sectiou,.o-f :the apparatuser Figure 1.

Figure 3 is a fragmentary detail, partly in section, and .on $311enlarged :scale, illustrating the means employed to c.onvey..aquantity-of shredded foil to the nozzle which delivers it to.a flashlamp bulb.

.Referring now to. the drawings, particularly Figure :1 thereof, thatportion of afoil shreddingapparatus shown ttherein is designated-by thegeneralreferenee numeral .10. The foilshredding apparatusdthmaybe-ofthettype -show-n anddescr-ibed inUrS. Patent .'2,69 9,-8-31for example. Shredded foil, asitdrops awayifrom-thezcutters .of .thefoil .shredding apparatus, is -drawn into =venturi .assemblies 112 .and14 through 'venturi feeding -.tubes :16 \and .18. respectively..Theventuri assembliesxare mounted .on brackets .20 attached 1 tothetableiZ-Z on which'ther foil shredding apparatus :ltlris disposed.

:Referring now ato Figure -3, .the -venturi assembly :14,-comprisesabody'member 24:having abore 26 extending -.therethrough, oneend of the borebeing fitted'with an outlet pipe 28, and-the otherendof'the borebeing 'pro- \videdwitha nozzle 30' to which arplug 32. is'attachedy the 111 48 32 in turnbeing connectedtoa source "of gas, suchgas airtfor example, under pressurethrough flexible tubing 54. Thus:fiSlOlI-lS ShI'ddCd by the foil shredding appa- :ratus.-10;.the flow.of-gas'under pressure through Lfiex'ibIe '-.t-ubing34,:.plug3-2:andnozzle '3ilzdrawsthe shredded foil .through't-he venturi feeding tube1-8 of venturi '14, into the bore261and1discharge it :through theoutletpipe'28. ,The venturieassernbly :12 is of similar construction and-;operatestin-the same :mannerras venturi assembly 14.

"Thesshredde'difoil.discharged from outlet pipe 28 '(Fig. 3.)ris'rreceived :by funnel *36 of 'venturi assembly' d and is dischargedthrough :outlet pipe 40 thereof "by the ad- :missiOJl ofcgas,s:such.as'air for :example, under pressure into the venturiassembly 38 through fiexible tubing 42,

--;plug .414. andnozzle :46. Venturi assembly 48 (Fig; 2) is of asimilar;constrnctio-n and operates f in the same manner ;as Venturirassem'bly38, except that its outlet pipe-411s much :longer rtha-n :outlet :pipe40 -of venturi assembly 38 lfOlil'BfiSOIlSiWhiGh will beapparentfrom-the description ibelowtoff the;remainder of the apparatus orthisinvention.

rThe shredded:foil dischargedfrom outlet pipe ill-(Fig. .:'3).-.isreceived by funnel .50 mounted on one end emolplowzshaftx52zofamotori54.The otheren'dof shaft El is zprovidediwithsa nozzle56 which is attachedthereto "by ameans of a.'chuck 53. The chuck 58 is prcvided'with sanO.ring seal 60' held':in place by aretaining ring 62-and mm 56.4. Theforce exerted by the gas entering the ven- :tufLSS-throug'h flexibletubing '42 is-sufiicient to drive the eshreddedifoil through the hollowshaft 52 and the nozzle 5'6 :into the :bulb 1. Similarly, shredded foilis *fed to "bulb .(:Fig. 2-) from venturi'48 and the venturi outlet pipe41. Venturis 38 and 48 are-supported from their respective associatedmotors 'Sdby means of arms 55 :depending from the motors, and clamps 57extending laterally frorn thelowerends of the arms 55 and attached tothe 'outlet'pipes dll and 41 respectively of the ventur'is 38 and 48.

Referring-now'to Figures 1 and 2, bulb 1 is supported by a'bu'lbholder.66 attached to an endless chain conveyor 68; and bulb 3 issupported by a bulb holder'70 attachedto an endless chain'convey'or'72.Conveyors 68 and 7 2 are provided with a plurality of bulb holders 6'6and 70=respectively for carrying bulbs'into position above and 'inregister with the apparatus just described toreceive a charge ofshredded foil therefrom. Each of the bulb-conveyors is provided with abulb orienting device, designated generallyby the reference numeral 71,which is mounted on a pedestal 73which supports idler shaft 75 ofconveyors 68 and 72. The bulb orienting device '7=1 comprises a pair ofjaws 77 which are opened and closed about the neck of a bulb by themotion transmitted thereto'by-suitable means from a roller79 whichrides-on a bar cam .81 attached to lift shaft 76.

"The apparatus for reciprocating the nozzle 56 into and out of the bulb1 to deliver a charge of shredded foil thereto will now be described.Delivery is effected when the nozzle 56, venturi 38 and venturi 14 arein the relative position in which they are shown in Figure 3. The

- mechanism for advancing the nozzle 56 and its associated parts intodelivery position is shown in Figure 2. The motor 54, which is connectedto the nozzle 56 by the chuck 58, and which is connected to the venturi38 by arm and clamp 57, is mounted on clamp 74 attached to the upper endof lift shaft 76. Lift shaft 76, which ex- -tends through and issupported by lift shaft housing 78 mounted on table 80, has a clamp 82attached to the lower end thereof. In order to prevent the lift shaftfrom rotatmg, the clamp 82 attached to the lower end of the lift shaftis provided with a slotted slide 84 which rides up and down on a guidebar 86 attached to and depending from the lift shaft housing 78. A link88, depending from link pin 90 which is mounted in and projectslaterally from clamp 82, connects the lift shaft clamp 82 to one end ofa cam arm 92. Cam arm 92 is pivotallymounted intermediate its ends onshaft 94 which is supported in Similar apparatus, operating in a similarmanner, is provided for delivering a charge of shredded foil to the bulb3. Cam shaft 102 on which cam is mounted, and stub shaft 103 on which aearn 105 similar to cam 100 15 mounted, are driven by a common drive(not shown) .unounted on the table 80, the casting 107 for housing aportion of this drive being mounted on top of table 80 as shown in Fig.2.

The means for energizing the motors 54, to effect rotation of thenozzles 56 will now be described, reference being made particularly tothe right hand side of Figure 2. Wire 106, from a source of electricalenergy not shown, 18 connected to a screw 108 disposed in housing 110 ofinsulating material mounted on table 80. The housing 110 is providedwith a bore within which a spring 112 is disposed. One end of spring 112is connected to screw 108 and the other end thereof is attached to oneend of an electrically conducting rod 114 mounted in housing cover 116which is slidably disposed on housing 110. A wire 118, attached to theother end of rod 114,

. extends through aperture 120 in housing cover 116 and is connected tomotor 54. A bracket 122, attached to both the housing cover 116 and acap 124 slidably disbe described,'reference being made particularly toFigures 1 and 2. Air from a source not shown is admitted into the systemthrough feed line 126 into filter 128. Four separate feed lines run fromfilter 128 to four separate pressure regulators 130. A feed line 132connects each of the pressure regulators to an air valve 134, theseveral air valves being attached to a mounting plate 136 supported by apair of standards 138, one of which is shown in Figures 1 and 2. Each ofthe air valves 134 is provided with a mercury switch 140 dependingtherefrom, the roller 142 of which rides on cam 144. The cams 144 aremounted on shaft 146 which is supported in bearing housings 148 mountedon standards 138; Feed lines 150 extending from air valves 134 areclamped to support bar 154 which is attached to table 80 by bolt 81.Flexible tubes 34, depending from venturis 12 and 14, are con- 4, nectedto the termini of two of the feed lines 150 at support bar 154.Similarly, flexible tubes 42, depending from venturis 38 and 48, areconnected to the termini of the other two feed lines 150 at support bar154.

The operation of the shredded foil feeding apparatus will now bedescribed, reference being made initially to Figure 2. The reciprocatingnozzle 56 of the shredded foil feeding assembly illustrated at the righthand side of Figure 2 is shown in the advanced or delivery position, i.e., the tip thereof has been moved inside the bulb 1 to deliver a chargeof shredded foil 5; whereas the nozzle 56a of the shredded foil feedingassembly illustrated at the left hand side of Figure 2 is shown in theretracted position, awaiting its turn to advance and deliver a quantityof shredded foil to bulb 3.

Advancement of the nozzle 56 from its retracted position to its advancedposition is effected by the cam 100 on cam shaft 102, through camfollower 98, earn arm 92, link 88, link pin 90, clamp 82 and lift shaft76. As the lift shaft 76 moves upwardly, it carries with it the motor54, the nozzle 56 which is attached to the hollow motor shaft 52, andthe venturi 38 which is supported from the motor 54 by arm 55 and clamp57. When the upward stroke of the lift shaft 76 has been completechthenozzle 56 is disposed inside bulb 1 (Fig. 3) and the funnel 36 ofventuri 38 is in alignment with the outlet pipe 28 of venturi 14. Withthe apparatus so disposed, the-nozzle 56 is ready to receive a charge ofshredded foil from the foil shredding apparatus 10 (Fig. 1) and deliverit into the bulb 1.

Actuation of the pneumatic system for supplying air under pressure tothe venturis 12, 14, 38 and 48 is synchronized with the reciprocation ofthe lift shafts 76 so that a blast of air is admitted to the shreddedfoil feeding system intermittently, i. e., when a nozzle 56 is inposition inside a bulb. Referring now to Figure 2, the two right handair valves 134 are shown in the open position, having been actuated bythe rotation of the shaft 146, through their respective cams 144,rollers 142 and mercury switches 140. Air from these two valves flows tothe venturis 14 and 38 throughthe two feed lines 150 and flexible utbes34 and 42 respectively. Air flowing through the venturi 14 drawsshredded foil from the foil shredding apparatus 10 (Fig. 1) throughfeeding tube 18 and discharges it through outlet pipe 28 into funnel 36of venturi 38 (Fig. 3). Similarly, air flowing through the venturi 38draws the shredded foil through funnel 36 and discharges it throughoutlet pipe 40 and into funnel 50 on one end of the hollow motor shaft52 with suflicient force to drive it through the shaft 52 and nozzle 56into the bulb 1. Rotation of the nozzle 56, which is preferably providedwith a delivery opening 53 in the side wall thereof like the nozzleshown in the copending application of Bennett et al. referred to above,effects a satisfactory distribution of the shredded foil within the bulb1.

The air valves 134 (Fig. 2) which were opened to admit air to theventuris 14 and 38, are now closed by the further rotation of shaft 146on which the cams 144 associated therewith are mounted, therebyterminating the flow of shredded foil to the nozzle 56. The returnstroke of the lift shaft 76 (Fig. 2), to withdraw the nozzle 56 from thebulb 1 to which a charge of shredded foil 5 has been delivered, iseffected by the further rotation of shaft 102 on which cam 100 ismounted. The conveyor 68 indexes one station, carrying away the bulbwhich has been provided with a charge of shredded foil and bringinganother bulb into loading position.

While the nozzle 56 and its associated mechanism is returning to itsrest position, the nozzle 56a (Fig. 2) and its associated mechanism isadvancing from the rest position to effect delivery of a charge ofshredded foil to bulb 3. Since the mechanisms employed and their mode of'operation are the same as those associated with nozzle 56, a detaileddescription thereof is believed to be unnecessary. 1

Frornthe foregoing, it is apparent that, in accordance withtlieprin'eiples ofthisint/e'ntion; not only is automaticapparatus'provided' for deliveringa charge'ot shredded foil to'fiashlamp bulbs'asftheyare advanced by a conveyortoa'loading station, butmaximum utilization of the output of a foil shredding machine isobtained by synchronizingtwo foil feeding mechanisms therewith and witht'wo"bulb conveyors'whereby shredded'foil is being fed'to' a bulbon'o'neconveyor by'one foil feeding mechanism while the other foir feeding"mechanism 'is re-' turning to its'rest'positio'n afteifhavingjust'delivered a charge ofishrtedddfdilto a bulb'on another conveyor.

WhatweeIaini is: I 7 p 1. Appara'tii's'for providing'lampbulbs with afilling of filamentary particles comprising: a nozzle throughwhich-filamentary particles may be' dischar ed; a conveyordisposed inoperative relationship with respect to said nozzle"f"or"carrying lam-bulbs sequentially into reg ister with said nozzle; means forreciprocating said nozzle into and out of a lamp bulb in registerth'erewith on said conveyor; meansfor'causing a flow of filamentaryparticles throughv said nozzle when saidnozzle is in the advancedposition of itsreciprocating. stroke; and means for rotating said nozzlewhen said nozzle is in the advancedlposition of its reciprocating stroketo efiect adistribution within the lampbulb of the filamentary par- Iticles flowing from said nozzle.

2. Apparatus for providing lamp bulbs with a filling of filamentaryparticles comprising: a nozzle through which filamentary particles maybe discharged; a conveyor disposed in operative relationship withrespect to said nozzle for carrying lamp bulbs sequentially intoregister with said nozzle; means for reciprocating said nozzle into andout of a lamp bulb in register therewith on said conveyor; pneumaticmeans for causing a flow of filamentary particles through said nozzlewhen said nozzle is in the advanced position of its reciprocatingstroke; and means for rotating said nozzle when said nozzle is in theadvanced position of its reciprocating stroke to efiect a distributionwithin the lamp bulb of the filamentary particles flowing from saidnozzle.

3. Apparatus for providing lamp bulbs with a filling of filamentaryparticles comprising: a reciprocable nozzle through which filamentaryparticles may be discharged; a conveyor disposed in operativerelationship with respect to said nozzle for carrying lamp bulbssequentially into register with said nozzle; a reciprocable venturiassembly, the outlet of which is in axial alignment with said nozzle;means for synchronously reciprocating said venturi assembly and saidnozzle whereby said nozzle is moved into and out of a lamp bulb inregister therewith on said conveyor; means, in communication with asource of filamentary particles, for introducing filamentary particlesinto said venturi assembly; means for actuating said venturi assembly toefiect a flow of filamentary particles therethrough and through saidnozzle into a lamp bulb when said nozzle is in the advanced position ofits reciprocating stroke; and means for rotating said nozzle when saidnozzle is in the advanced position of its reciprocating stroke to effecta distribution Within the lamp bulb of the filamentary particles flowingfrom said nozzle.

4. Apparatus for providing lamp bulbs with a filling of shredded foilcomprising: a reciprocable nozzle through which shredded foil may bedischarged; a conveyor disposed in operative relationship with respectto said nozzle for carrying lamp bulbs sequentially into register withsaid nozzle; a stationary venturi assembly in communication with asupply of shredded foil; a reciprocable venturi assembly movable intofoil-receiving relationship with respect to said stationary venturi, andsaid reciprocable venturi assembly having an outlet in axial alignmentwith said nozzle; means for synchronously reciprocating said nozzle andsaid reciprocable venturi whereby said nozzle is moved into and out of alamp bulb in register therewith on said conveyor; and said reciprocableventuri is moved into and out of foil-receiving relationship withrespect" tosaid-stationaryyenturi; and'meansfor effecting a flow ofshredded foil from asupply thereof through said stationary venturiassembly, said reciprocable venturi assembly and said nozzle into a lampbulb when said nozzle and said'reciprocable venturi assembly are in theadvanced position of their reciprocating stroke.

5. Apparatus for providing lamp bulbs with a filling of shredded 'foilcomprising: a reciprocable nozzle through whichshredded foil may bedischarged; a con veyor disposed in operative relationship with respectto said nozzle for carrying lamp bulbs sequentially into register withsaid nozzle; a stationary venturi assembly in communication with asupply of shredded foil; a reciprocable venturi assembly mov'ableintofoil-receiving relationship with respect to said stationary venturi; andsaid reciprocable venturi assembly having an outlet in axial alignmentWith-saidnozz'le'; means for syn= chronously reci rocating said nozzleand said reciprocable venturi whereby said' nozzle is moved into and outof 'a lamp bulb in register'therewith on said conveyor, and saidreciprocable venturi is moved into and out of foilreceiv-ingrelationship with respect to said stationary venturi; means foretfe'cting a flow of shredded foil from a supply thereof through saidstationary venturi assembly, said reciprocable venturi: assembly andsaid nozzle into a lamp bulb when said nozzle and said reciprocableventuri assembly are in the advanced position of theirreciprocatingstroke;; and means: forrotating said nozzle when saidnozzle is in the advanced position of its reciprocating stroke to efiecta distribution within the lamp bulb of the shredded foil flowing fromsaid nozzle.

6. Apparatus for providing lamp bulbs with a filling of filamentaryparticles comprising: a pair of nozzles through which filamentaryparticles may be discharged; a pair of conveyors, each of which isdisposed in operative relationship with respect to one of said pair ofnozzles, for carrying lamp bulbs sequentially into register therewith;means for alternately reciprocating said pair of nozzles into and out oflamp bulbs in register therewith on said conveyors; and means forcausing a flow of filamentary particles alternately through one and thenthe other of said pair of nozzles when said nozzles are in the advancedposition of their reciprocating strokes.

'7. Apparatus for providing lamp bulbs with a filling of filamentaryparticles comprising: a pair of nozzles through which filamentaryparticles may be discharged; a pair of conveyors, each of which isdisposed in operative relationship with respect to one of said pair of Inozzles, for carrying lamp bulbs sequentially into register therewith;means for alternately reciprocating said pair of nozzles into and out oflamp bulbs in register therewith on said conveyors; means for causing aflow of filamentary particles alternately through one and then the otherof said pair of nozzles when said nozzles are in the advanced positionof their reciprocating strokes; and means for rotating said nozzles whensaid nozzles are in the advanced position of their reciprocating strokesto effect a distribution within the lamp bulbs of the filamentaryparticles flowing from said nozzles.

8. Apparatus for providing lamp bulbs with a filling of filamentaryparticles comprising: a pair of reciprocable nozzles through whichfilamentary particles may be discharged; a pair of conveyors, each ofwhich is disposed in operative relationship with respect to one of saidpair of nozzles, for carrying lamp bulbs sequentially into registertherewith; a pair of reciprocable venturi assemblies the outlet of eachbeing in axial alignment with one of said pair of nozzles; means foralternately reciprccating each venturi assembly and the nozzle incooperative relationship with respect thereto whereby the said nozzlesare moved into and out of lamp bulbs in register therewith on saidconveyors; means, in communication with a source of filamentaryparticles, for alternately introducing filamentary particles first intoone 7 andthen into the other of said pair of'venturi assemblies; andmeans for actuating saidrpair of venturi assemblies alternately toeffect a flow of filamentary particles therethrough and through thenozzles in cooperative relationship with respect thereto into the lampbulbs when said nozzles are in the advanced position of theirreciprocating strokes.

9. Apparatus for providing lamp bulbs with a filling of filamentaryparticles comprising: a pair of reciprocable nozzles through whichfilamentary particles may be discharged; a pair of conveyors, each ofwhich is disposed in operative relationship with respect to one of saidpair of nozzles, for carrying lamp bulbs sequentially into registertherewith; a pair of reciprocable venturi assemblies the outlet of eachbeing in axial alignment with one of said pair of nozzles; means foralternately reciprocating each venturi assembly and the nozzle incooperative relationship with respect thereto whereby the said nozzlesare moved into and out of lamp bulbs in register therewith on saidconveyors; means, in communication with a source of filamentaryparticles, for alternately introducing filamentary particles first intoone and then into the other of said pair of venturi assemblies; meansfor actuating said pair of venturi assemblies alternately to effect aflow of filamentary particles therethrough and through the nozzles incooperative relationship with respect thereto into the lamp bulbs whensaid nozzles are in the advanced position of their reciprocatingstrokes; and means for rotating said nozzles when 'said nozzles are inthe advancedrposition of their reciprocating strokes to effect adistribution within the lamp bulbsof the filamentary particles flowingfrom said nozzles.

10. Apparatus for providing a lamp bulb with a filling of filamentaryparticles comprising: a nozzle through which filamentary particles maybe discharged; a conveyor disposed in operative relationship withrespect to said nozzle forcarrying lamp bulbs sequentially into registerwith said nozzle; means for effecting relative displacement of saidconveyor and said nozzle whereby said nozzle is disposed in a lamp bulbin register therewith on said conveyor; means for causing a flow offilamentary particles through said nozzle; and means for rotating saidnozzle, when it is disposed in a lamp bulb, to effect a distributionwithin the lamp bulb of the filamentary particles flowing from saidnozzle.

References Cited in the file of this patent UNITED STATES PATENTS833,637 Sheffield Oct. 16," 1906 1,859,562 Huston May 24, 1932 2,273,735Raymer Feb. 17, 1942 2,347,046 Geiger Apr. 18, 1944 2,547,606 StallerApr. 3, 1951 FOREIGN PATENTS 7 239,948 Great Britain Sept. 24, 1925

